如何在默认的后退按钮单击中将requestCode从子活动返回到父活动

Question

I am having using onActivityResult method in my ParentActivity and i call a ChildActivity from my ParentActivity in a Button click. In my ChildActivity when I click the default back button and when it goes to my ParentActivity , I am not getting my requestCode that i set in my ChildActivity in onStop() method by:

setResult(2);

How can I return my requestCode from my ChildActivity to ParentActivity when I click back button.

Please help me.

Thanks in advance.

Here is ma code:

      //Parent activity
      protected void onActivityResult(int requestCode, int resultCode, Intent data) {
            Toast.makeText(this,resultCode+"", Toast.LENGTH_LONG).show();
            if(resultCode==2){
                finish();
            }
        }

    //Child activity
      protected void onStop() {
           setResult(2);
           super.onStop();
            }
 protected void onPause() {
           setResult(2);
           super.onStop();
            }

Answer 1

You can use this code in your child activity

@Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        if(keyCode == KeyEvent.KEYCODE_BACK){
            setResult(RESULT_OK);
            finish(); // If you have no further use for this activity or there is no dependency on this activity
                    return true;
        }
        return super.onKeyDown(keyCode, event);
    }

This piece of code will return result ok code from your child activity to parent activity

Now in your parent activity in

@Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        switch (requestCode) {
        case 2:
            if(resultCode == -1){
                // Here you write your code which you have to write on result receive
            }
            break;

        default:
            break;
        }
        super.onActivityResult(requestCode, resultCode, data);
    }

Let me know if this helps you

Answer 2

覆盖onBackPressed（）比覆盖onKeyDown（）更好